Heretofore, various methods and means have been provided to cover an opening in the damaged hull of a ship resulting from a collision or the like.
Such prior art methods and means have included a flexible covering utilized with magnets to hold the covering onto the metal hull of a ship over an opening. For example, U.S. Pat. No. 770,078 dated Sep. 13, 1904 shows a magnetic curtain for covering leaks in ships with the curtain being unrolled alongside the ship over a hole provided in the hull. Magnets secured to the flexible curtain assist the water pressure in holding the curtain against the hull.
U.S. Pat. No. 932,720 dated Aug. 31, 1909 shows means for closing holes in a steel hull in which a series of magnets may be energized for securing an inflatable bag or blanket to the hull. The blanket is made of a strong material impervious to water or air, such as canvas and rubber combined. U.S. Pat. No. 3,669,055 dated Jun. 13, 1972 shown an apparatus and method for sealing a vessel opening in which anchoring devices for a cover over an opening in a hull are provided adjacent lower corners of the cover and are secured to the hull by electromagnets. The cover is formed of an elastomeric material such as rubber and the outer layer has an armored covering to protect the cover form sharp jagged edges about the opening in the hull.
Such prior art means such as the above, do not utilize electromagnets which may be precisely controlled individually or sequentially in predetermined groups for sequentially mounting flexible covering means over an opening in the hull from one end of the covering means to the opposite end thereof.